Manufacture of artificial silk



March 16, 1937. H. A. SCHRENK MANUFACTURE OF ARTIFICIAL SILK Filed April 25, 1956 attozmq N 325x13 Z p I Patented Mar. 16, 1937 PATENT OFFICE MANUFACTURE OF ARTIFICIAL SILK Hans Alwin Schrenk, Arnhem, Netherlands, as-

.signor to American Enka Corporation, Enka,

N. 0., a corporation of Delaware Application April 25, 1936, Serial No. 76,471

, l In Germany April 26, 1935 2 Claims.

This invention relates to the production of artificial textile strands and more particularly to a methodof and apparatus for manufacturing artificial silk strands.

In the manufacture of artificial silk,-a wellknown process is the so-calledwet spinning meth od, in the practice of which a cellulosic solution is extruded through the fine orifices of a spinnerette to form endless filaments. The filaments, which are originally viscous liquid, pass continuously through a liquid bath, Said bath includes constituents whichreact with the filaments to progressively coagulate the material thereof and impart thereto sufficient strength to enable their convenient handling during subsequent treatment without accidental rupture and, ultimately, such solidity that the filaments will possess definite tensibility. The filaments are then advanced in parallel relationship from the bath, wound upon a collecting device and subjected to various essential treating operations, such as washing, desulphurizing, bleaching and drying. The process of coagulation in the bath develops as the filaments progress therethrough,

and it is the normal procedure to control the pas sage of the filaments so that coagulation is practically complete at the time the filaments are drawn from the-bath at the point farthest from "the spinnerette.

Because single filaments, even after strengt ening in the coagulating bath, are characteristically too tenuous for normal utilization by fabric manufacturers, a further important step in the process is the assembling of the several filaments intoa composite strand or yarn. One method of accomplishing this is to place a loaded windingdevice upon a twisting machine and transfer the filaments during twisting to a yarn take-up reel. Rewinding is expensive and many attempts to obviate it in this connection have been made.

Proposals to eliminate said rewinding operation include twisting the filaments together to form the .yarn while the filaments are still in the coagulating bath. Since the twisting of the filaments takes place at the point offering the least resistance, i. e., immediately adjacent to the spinnerette where they first encounter the coagulating bath, their incompletely coagulated condition causes the individual filaments to stick together or fuse',- or even break, and the composite nature of the strand is thereby destroyed. Not only is the product thus rendered inferior in strength, but subjection-of the filaments to the requisite continued coagulation during the balance of their progress through the bath causes the twist to become set therein and so critically reduces flexibility as to render the product useless for the purposes intended.

Accordingly, it has been attempted to extrude the filaments from the rotating spinnerette into a relatively stationary or quiet bath. Although this method produces a twist of relatively high angularity with respect to the axis of the strand, the freshly spun filaments encounter considerable resistance therein, to the extent that they are frequently torn, become fiufiy and are otherwise damaged to result in an inferior product.

The present invention is directed to axially aligned stationary and rotating spinning baths, and contemplates the extrusion of a cellulosic solution through a rotating spinnerette to form filaments therefrom which pass through a column of spinning bath fluid. Said column rtates concentrically with the spinnerette and with substantially the same angular velocity as the filaments, so that no tearing or twisting action can occur. The filaments advance in substantially parallel relationship through the rotating bath until they have sufiiciently coagulated to strengthen them to withstand twisting without sticking or other deleterious deformation. The rate of coagulation and speed of the filaments being fairly constant, the optimum conditions for twisting are at a point spaced considerably from the spinnerette; and twisting is accomplished adjacent to said point without possibility of tearing or accidental rupture of the filaments by passing thefilaments in a tortuous path through an eccentric die. The twisted filaments pass into the stationary bath where. coagulation proceeds to completion, the finished strand being withdrawn and wound upon any suitable take-up for appropriate cleansing and drying.

One object of the invention is to provide a method of manufacturing strands which will be efficient and otherwise economically justified.

Another object of the invention is to provide a method of manufacturing strands from artificial silk filaments wherein twisting is conveniently combined with the coagulation step.

Another object of the invention is to provide a method of manufacturing strands from artificial silk filaments, wherein the twisting operation is combined with the coagulation step to form a superior and cheaper product.

of apparatus for the efficient and reliable manufacture of artificial silk.

'Another object of the invention is the provision of simple and dependable apparatus for forming an artificial silk strand wherein twisting of the traveling filaments is caused to occur at a fixed point during their progress whereby optimum strand assembly conditions may be uniformly realized.

Other objects and advantages will be apparent from the following detailed description, considered in connection with the accompanying drawing, forming a part thereof, in which the figure is a schematic view in vertical section of my form of apparatus for practicing the invention.

Referring to the drawing, a spinnerette fastened to the upper end 2 of a vertical shaft 3 by any suitable means, is supplied with spinning material, for example, viscose, through an axial passage 4 in the shaft 3. Said shaft is driven by a pulley 6 for rotation in bearings 1 and 8 on supports '9 and H cushiohed by rubber rings |4- |4 spaced by flanges |6--'|6. 'Rub'ber ring I1, fast on the shaft 3, forms a resilient bearing therefor; and an additional stabilizer for the shaft is provided in fly-wheel I8.

The upper end of shaft l has an outwardly extending enlarged portion IE], to which is fastened a coaxial cylindrical vessel 2| constituting a primary coagulating bath receptacle. Bath vessel 2| is flanged at 22 and secured by screw ring 23 to rotate with shaft 3. The top of the vessel 2| is fitted with a cover 24, fastened by any suitable means. Said cover 24 includes a nozzle or die section 26, extending concentrically within the vessel 2 I. Cover 24 has a central bore 21 and an oblique channel or strand die opening 28 communicating with the central bore 21 at 29.

It will be observed that the strand die opening 28 extends radially diagonally outwardly from the center so that its lower opening is considerably removed from the axis of the vessel 2 and shaft 3,.for a purpose to be explained hereinafter. The central bore leads into a widened coaxial orifice 3| communicating with additional oblique channels 32 and 33. The vessel 2| is drained by means of one or more holes 34 formed just above the screw ring 23.

Above the primary spinning bath 2| is a secondary spinning bath receptacle 35, widened out at its lower portion to form a cylindrical casing 36 enclosing the primary bath vessel 2 Supported at its base is a communicating outlet vessel 3-1. The receptacle 35 is supplied with spinning bath solution S through a pipe 38.

At the bottom of the receptacle 35 is a coaxial pipe 39, which may be resiliently mounted. Pipe 39 projects downwardly into the orifice 3|, leaving a small clearance between pipe 39 and the walls of said orifice.

Viscose is supplied to shaft 3 through pipe 40 thereon, inserted for free rotation in pipe 4| which in turn is inserted into a tube 42 leading to any source of supply, not shown.

A suitable collecting device such as shown at 43 is located above the receptacle 35.

In carrying out the process of the invention the pulley 6 is driven to rotate shaft 3, spinnerette tank 2| and cover piece 24. The bath fluid is led through pipe 38 into the stationary tank 35, through pipe 39, into the orifice 3| in the cover 24, thence through the channels 21, 28, 32 and 33 into the rotating bath receptacle 2|. The fluid flows constantly into tank 2| to keep it full,

and is discharged at the bottom through opening 34 into outlet chamber 31.

The flow of fluid into pipe 39 is suitably regulated to allow an overflow through opening 3| around pipe 39. It will be understood that the influx of fresh fluid will flow principally through oblique channels 32 and 33. The centrifugal force set up by the rotary motion 'of tank 2| will cause the fluid flowing into it through oblique channels 32 and 33 to conform to the rotation thereof, so that the fluid in the tank will become a cylindrical column of fluid revolving with substantially the same angular velocity as the spinnerette.

When the spinning solution is forced into the shaft 3 and out through spinnerette into revolving primary receptacle 2|, the coagulating filaments F are led upward through the rotating column of bath fluid to the channel or die opening 28. Thence it passes to the pipe 39 and upward through the substantially stationary bath in receptacle 35, and thereafter to the take-up or collecting device 43. I v I Inasmuch as the bath receptacle 2 I, cover piece 24, bath fluid therein and the spinnerette all rotate at the same angular speed, the filaments are not twisted on extrusion from the spinnerette or at any point substantially below the cover 24. Should the filaments be led in a straight line upward through the axial bore 21 of the cover 24, the rotary motion of the relatively parallel filaments, conforming to the rotary motion of the bath, would not entirely offset the tendency of the filaments to become twisted at a point within the primary spinning bath adjacent to the spinnerette; and the danger of the freshly formed filaments sticking together and becoming otherwise damaged would be present. Therefore, the filaments are deflected from their normal axial path and caused to assume a tortuous one through the oblique channel 28 before again being directed into the axial path at the point 29 where die channel 28 opens into bore 21. Die channel 28 thus operates as an eccentric thread guide revolving about the central bore as an axis, and twisting of the bundle of filaments rotating therewith takes place from that point upward through the stationary bath to the collecting device, thus providing a uniform, normally twisted product.

If, during the process of manufacturing artificial yarns and the like, the cellulosic solution produces filaments which coagulate sufii'ciently in the rotating bath, then it is unnecessary to provide an additional stationary bath in combination therewith.

While the foregoing constitutes a preferred embodiment and mode of practice of my invention, it is clear that numerous changes may be made therein without departing therefrom and the invention is not to be limited other than by the'scope of the appended claims.

What I claim is:

1. In an apparatus for the manufacture of artificial silk, a rotating assembly of spinnerette and spinning bath receptacle, a stationary bath receptacle alined with the rotating assembly, means for advancing filaments from the spin nerette and through the respective bath receptacles, and means eccentrically disposed with re- .spect to the axis of the assembly for causing a twisting to occur in the filaments at a point in the rotating bath receptacle adjacent to the stationary bath receptacle.

2. In an apparatus for the manufacture of artificial silk, a rotating assembly of spinnerette and spinning bath receptacle, a stationary bath receptacle alined with the rotating assembly, means for advancing filaments in an axial path from the spinnerette and through the respective bath receptacles, and die means eccentrically disposed with respect to the axis of the assembly for causing a twisting to occur in the filaments at a point in the rotating bath receptacle remote from said spinnerette.

HANS ALWIN SCHRENK. 

